In established regions or municipalities, particularly those that are densely populated, underground pipes carry steam, hot water, or other heat and energy source materials, to commercial, industrial, and residential buildings. In order to reduce heat dissipation through these, mostly metallic, pipes they are insulated during installation. However, due to shortcomings in design or workmanship, or damage from environmental elements or aging, some of the original insulation systems fail as effective barriers to heat loss.
Generally, the design of regional or municipal underground piping uses metal pipes laid inside concrete or tile conduits. Between the steel carrier pipes and the outer conduits, there exist open air spaces. Thus, insulating materials are needed to fill the gap between the inner metallic pipes and the outer concrete or tile conduits. These air spaces are filled with a closed cell, high temperature, plastic foam insulation (polyisocyanurate foam) as a means of reinsulating the underground lines. This process, also known as “CondufillSM.”, uses a high temperature Teflon hose to apply the insulating foam through a vacuum, excavation or a manhole. Such process, however, requires a dispensing system with a suitable metering device to supply the materials which make up the insulating foam to the injection hoses for application to the conduit air spaces.